1. Field of the Invention
This invention relates generally to motor control, and particularly to starting current control for a motor.
2. Description of Prior Art
When an a.c. servomotor or the like is driven by commercial frequency power source whose impedance is relatively high, flicker is apt to occur in lights connected to the commercial a.c. line. In order to reduce such flicker in conventional arrangements, a maximum limit of a starting current of a motor is decreased.
However, when the starting current is simply reduced, an accelerating period of time of a motor increases. Moreover, the reduction in starting current results in the reduction in instantaneous torque of the motor deteriorating starting characteristic. As a result, necessary torque which is required on start or inching of a short period of time is not fully generated.